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An astronomical century of discovery at the Dominion Astrophysical Observatory

Dominion Astrophysical Observatory centennial

100 years ago, on May 6, 1918, the "first light" fell onto photographic plates at the Plaskett Telescope, opening the Dominion Astrophysical Observatory and putting Canada onto the world stage of astrophysics.

The Plaskett Telescope was Canada's first major "big science" project to be funded publicly. For more than three decades, it enabled major discoveries in astronomy as one of the three largest telescopes in the world. In the decades that followed, the staff at the observatory have continued this legacy of scientific discovery and advanced engineering, working on some of the most powerful telescopes around the world, and advanced data management and analysis techniques, to broaden our understanding of the universe.

About the Dominion Astrophysical Observatory

When the Plaskett telescope was first built in 1918, it was home to two researchers, and one office building which was only built in 1922.

Today, the Dominion Astrophysical Observatory (DAO) is one of two national observatories managed by the Herzberg Astronomy and Astrophysics Research Centre, a part of the National Research Council of Canada. It is home to astronomers who lead scientific discovery, and engineers who develop advanced instrumentation for telescopes that peer further into the universe than ever before, making discovery possible. The Canadian Astronomy Data Centre, based at the DAO, provides data services that are used by 60% of astronomers around the world to allow them to carry out research.

The Research Centre manages Canada's participation in international observatories, opening the doors for Canadian astronomers and industry to work on some of the most ambitious projects in astronomy and the greatest puzzles about our universe.

100 years of discovery

Long description of the infographic "Dominion Astrophysical Observatory - 100 years - 1918-2018"

1930s - Accurately determined, for the first time, the size and rotation of our Milky Way's spiral disk. (Photo: Dan Posey)

Our modern understanding of the size, mass and motions of the Milky Way emerged in the early 1930's when John Stanley Plaskett, then Director of the DAO, and staff astronomer Joseph Algernon Pearce, made observations that enabled them to measure the size of the Milky Way and our Sun's position in it.

1970 - Began to manage Canada's role in some of the world's most powerful telescopes, when DAO joined the National Research Council Canada. (Photo: ESO/C.Malin)

As part of the NRC, the Observatory's mandate grew. Telescopes had advanced to a point where the size and expense necessitated multiple, international partners. To maintain Canada's prominent position in astronomy, the Observatory was tasked with managing Canada's participation in international telescopes, providing a gateway for Canadian astronomers, engineers and industry to become involved in some of the largest telescopes in the world.

1974 to present - Conceived and built game-changing instruments for the world's largest telescopes.

From building instruments for the Canada-France Hawaii Telescope, to developing the sensitive receivers for ALMA, and developing adaptive optics for the Thirty Meter Telescope, the NRC has worked closely with our partners and industry to advance our ability to see farther into the universe.

1983 - Provided first definitive proof of a stellar mass black hole.

Black holes are very difficult to find! Because they are invisible they can only be identified and studied through their impact on nearby stars or matter. Two DAO astronomers and an American colleague provided definitive evidence for the first stellar mass black hole. They discovered it around a massive star in the Large Magellanic Cloud.

1986 to present - Made big data manageable for 60% of astronomers around the world, at the Canadian Astronomy Data Centre (CADC).

Processing photos of space is not a simple point-and-shoot activity like your digital camera, and for many years, it could take weeks to analyze data in order to render a single photo. The CADC helped to change that, and make data and images easily accessible to astronomers. Over 60% of the world's astronomers use the CADC's services, downloading more than 1 Petabyte of data each year. It is one of three sites in the world to support data for the Hubble Space Telescope. It now provides pioneering cloud computing capabilities for users to access and analyze big data.

1987 to present - Developed the leading software to measure thousands of stars in crowded fields: DAOPHOT.(Photo: CFHT/Coelum)

Measuring the brightness of stars has been important for astronomy since ancient times. The advent of digital detectors allowed astronomers to record exceptionally precise images of the sky but presented a challenge: how to make accurate measurements of the brightness of stars, particularly when the star images are so close together that they overlap. A DAO researcher developed powerful software called DAOPHOT in 1987 to address this problem. This software was released freely to astronomers worldwide. Today DAOPHOT, which is continually being improved by its developer, is the most widely used software for this purpose, and has supported Nobel Prize winning discoveries.

1988 to present - Pioneered adaptive optics for sharper images, comparable to those taken from space.

Currents in our atmosphere cause waves, similar to the heat waves you see over a road on a hot day. To take the "twinkle" out of the stars, DAO staff partnered with the Université de Montréal, to construct the High Resolution Camera (HRCam) for CFHT in the late 1980's. This allowed Canadian astronomers to do research that people thought could only be done from space, and launched Canada's long history in developing advances in the field of adaptive optics for astronomy.

2008 - Took the first direct picture of planets orbiting a nearby star using advanced techniques to blot out the brightness of the star.

Because distant stars are so bright, it is extremely difficult to see and study the fainter planets that surround them. Thanks to advanced adaptive optics techniques pioneered at the DAO, we were able to take the first "portrait" of a family of planets orbiting a star 130 light years away from Earth.